Docs: 修复事件后处理函数类型 docstring 错误 #3311

Job	Run time
Test Coverage (3.10, macos-latest)	1m 22s
Test Coverage (3.10, ubuntu-latest)	30s
Test Coverage (3.10, windows-latest)	1m 5s
Test Coverage (3.11, macos-latest)	1m 5s
Test Coverage (3.11, ubuntu-latest)	31s
Test Coverage (3.11, windows-latest)	1m 5s
Test Coverage (3.12, macos-latest)	1m 18s
Test Coverage (3.12, ubuntu-latest)	33s
Test Coverage (3.12, windows-latest)	1m 33s
Test Coverage (3.8, macos-latest)	58s
Test Coverage (3.8, ubuntu-latest)	35s
Test Coverage (3.8, windows-latest)	1m 22s
Test Coverage (3.9, macos-latest)	1m 58s
Test Coverage (3.9, ubuntu-latest)	41s
Test Coverage (3.9, windows-latest)	1m 16s
	15m 52s

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